The extra part of the URL is due to the System - Language Filter plugin being enabled. That will try to create a URL that is specific to the user that is visiting your page and is meant for multi-lingual sites. If you don't have a multi-lingual site, you should probably disable that plugin. If that's already disabled, it means that you have some other language extension installed that's changing the URL to a language-specific URL.
Hope that helps explain the URL issue.
As to your other questions, in the SCLogin module, there is an option to show the user's avatar. For Zoo, I'm not sure how their comment system works. However, if they're using the Facebook Comments widget, it likely has a different login than what we provide in JFBConnect. To post a comment, Facebook only requires that you are logged into Facebook. To register on your site, you need to "Approve" the Facebook Application for that site, which has it's own permissions like letting you (the admin) fetch the user's email address and profile information. There's not a way to hook into the Comment login functionlity, which is for basic "Are you logged into Facebook" with your site's registration which has much more stringent requirements.
If you have any questions, or need more information on the above, just let us know.
Thanks,
Alex